The present invention relates to a method of increasing the stability and reducing the microbial counts of both spice or herb oleoresin and the residual cake from which the oleoresin has been extracted. The process simultaneously extracts and concentrates the principal flavor, aroma, color, and other active components, produces a concentrated and standardized food-grade extract of active components, and a standardized food-grade residual solid, with both the extract and residual solids having significantly reduced microbial counts and frequently also improved stability.
Concentrated extracts of spices and herbs are universally used for flavoring and coloring of food, beverages, and pharmaceuticals. These extracts are traditionally used where a standardized, sterile, and uniform concentrate offers the benefits of control which are inherently difficult to obtain from raw spice or herb, or where the bulk of the raw material is not needed or undesirable.
Ground spice and herb solids are universally used for flavoring, coloring, and imparting otherwise favorable characteristics to food and beverages where the bulk, functional characteristics, and appearance of the food or beverage is important.
Dried spices and herbs, most often in their ground form, are used in the preparation of food and beverages to add flavor, aroma, color, and preservative properties that make the food more palatable and appealing. The dried spices, ground or unground, are usually added to the food or beverage during preparation at such a point in the preparation that time is allowed for the principal components of interest to be extracted into the food or beverage to impart the desired combination of attributes to the food or beverage. Further, as spices and herbs are notoriously known to have inconsistent levels of the flavor, aroma, color, or antioxidants, it is commonly required that spices of varying levels of the principal components of interest be blended to make a final product that is consistent with regard to the principal components of interest to achieve predictable and repeatable performance with respect to the flavor, aroma, color, or antioxidant release into the food or beverage system in which they are used. This is a costly and time consuming process.
As suggested in prior art, much of the flavor, aroma, and/or color often is not effectively transferred to the food or beverage. U.S. Pat. No. 2,507,084 overcomes this obstacle of under-utilization of the principal components of interest by first extracting the principal components of interest and subsequently coating the spent spice from the extraction process with a portion of the extract originally removed, thereby extending the useful amount of flavor and aroma that can be derived from a given quantity of spice. It is also disclosed that this process derives value from the exhausted spice solids, from which the flavor, aroma, color, or antioxidants have been removed, which would otherwise be a waste product. This is a complicated and costly process for recovery of the maximum value of the spice and its principal components of interest.
Traditional extraction processes for the manufacture of concentrated extracts (concentrated several fold as compared with the raw material) involve not only the use of various non-edible solvent systems, but also a large proportion of solvent in relation to the compounds of interest. Many require the use of petroleum distillates, chlorinated solvents, or highly flammable solvents which must be eliminated almost completely from the finished products to make them safe for consumption. These systems require expensive distillation equipment and special precautions must be taken to ensure worker safety and to limit environmental impact. The intensive processing required often destroys, modifies, or loses some of the more unstable compounds, delicate aromas, flavors, or pigments. More significantly, the last traces of undesirable non-edible solvents are very difficult to separate from the concentrated extract. The residual solid must necessarily contain the same residual non-edible solvents, which are removed only with difficulty. Such residual solvents limit the potential use of the residual solid for human consumption, and are potential environmental contaminants.
Other concentration techniques rely on high pressure equipment to obtain good solvating properties from gases, e.g., liquid or supercritical CO.sub.2 (U.S. Pat. No. 4,490,398). High pressure liquefied or supercritical gas extraction requires expensive equipment and has limited solvating abilities for some compounds requiring the addition of cosolvents, or solvents such as propane and butane, which are also difficult to control and may be environmentally sensitive or undesirable in a finished product.
Following extraction and desolventization, the concentrated extract is often standardized with edible solvents and emulsifiers to provide a concentrate with reproducible levels of the active or principal compounds of interest to the user.
In an effort to overcome the shortcomings and risks associated with the above-mentioned processes, extraction has been carried out using edible solvents such as vegetable oils or lard. Typical extraction procedures are disclosed in U.S. Pat. Nos. 3,732,111; 2,571,867; and 2,571,948. These methods require a relatively large volume of solvent in relation to the compounds of interest and result in a dilute extract which is limited in its application and which has few of the advantages of the concentrates which can be produced using volatile solvents.
U.S. Pat. No. 4,681,769 discloses a method for simultaneously extracting and concentrating in a series of high pressure countercurrent mechanical presses using relatively small amounts of vegetable oil as the solvent in an attempt to overcome the problem of dilution inherent in earlier processes. This method suffers from severe limitations in temperature and pressure ranges in an attempt to avoid unacceptable oxidative damage, color loss, yield losses, and flavor changes with the final result being that contact times must be unduly extended for up to 16-24 hours, adding greatly to the cost of the process. Extraction cycle times are unduly long for a given size pressing operation, and the process does not provide for a controlled degree of browning or for sterilization of the extract or of the residual solid. It is also limited to temperatures of less than 100.degree. F. to avoid alleged undue oxidation and thus it does not allow for the use of edible solvents which have a melting point of more than 100.degree. F. or which are highly viscous at temperatures of less than 100.degree. F. Maximum pressures of up to about 500 PSI (cone pressure) are claimed and this severely limits the efficiency and throughput rate for a given size pressing operation, as shown by the disclosure of this patent.
Traditional methods for the sterilization of ground spices and herbs involve the use of extremely toxic substances such as ethylene oxide or methyl bromide, irradiation, or steam and moisture treatment to reduce plate counts to less than 100,000. Chemical sterilization and irradiation of spices and herbs are disagreeable to the consumer because of the perceived risk of residual chemicals and/or radiation remaining in the plant matter and, as a result, several processes using added moisture, such as water or steam, at elevated pressures have been developed as alternatives. Typical sterilization procedures are disclosed in U.S. Pat. Nos. 4,210,678, 4,790,995, and 4,910,027. All sterilization processes are inherently costly in that they require a separate processing step or steps to accomplish the sterilization, and also present the possibility of further degrading the more unstable components. Addition of moisture or water vapor, as disclosed in U.S. Pat. Nos. 4,210,678 and 4,910,027, prior to or during the heating and sterilization process results in a cooked aroma not typical of the fresh, dehydrated spice or herb and also results in steam distillation and loss of some of the volatile flavor and aroma constituents.
U.S. Pat. Nos. 4,790,995 and 4,910,027 require the addition of a coating of animal protein to protect the spice from the loss of volatile aroma compounds during the sterilization process with water vapor. U.S. Pat. No. 4,210,678 requires bringing the moisture of the spice to above 8-14%, in some cases up to 16-20%, and holding the spice for an extended period of time prior to sterilization to equilibrate the moisture. This additional step is costly and time consuming. In the case of Capsicums, severe browning and off aromas and flavors are developed in the presence of moistures in excess of 10% at elevated temperatures above 180.degree. F.
Traditional methods for controlling the brownness or degree of caramelization of Capsicum solid to enhance its visual appearance involve the use of elevated temperatures and the addition of vegetable or animal fats or oils to bring up the surface color and luster of the ground spice. This requires a separate and costly processing operation.
Above all, there is the unsolved problem of obtaining satisfactory yields, quality, and throughput rates of acceptable extract having an acceptable content of active principle in the edible solvent without undesirable oxidative damage to, and reduced stability of, the principal compounds of interest, while at the same time providing for simultaneous sterilization of both the herb or spice solid and extract.
Obviously, existing prior art procedures leave much to be desired, and it is a primary objective of the present invention to provide a procedure for the production of sterilized spice and herb products having enhanced stability and which otherwise obviates the shortcomings of the prior art.